once a year i run a gallon of acetone to 10 gallons of 92 just to clean out my fuel system. never noticed a power or fuel mileage increase. lotsa impurities in the junk they try to sell you at the pump today ( almost every fuel station here is switching to E10). i've seen claims of 5, 10, even 20mpg increases, if that was the case, everybody and their uncle would be selling the stuff. i'll just stick with my R10.